The installation of a window typically entails lifting the window up to the vicinity of the window opening, and then manually manoeuvring the window into the desired position in the opening. This can be a difficult and time-consuming procedure, particularly with heavy window units. It can also be hazardous, because if the workers installing the window lose their grip on the window before it has been securely anchored into position, the window can fall to the ground, injuring the workers and others on the ground. This hazard is naturally greater when windows are being installed in multi-level buildings.
One example of an attempt to address these problems is found in PCT Application PCT/W088/01670 (Harrison). This invention provides a lifting harness to be fitted to the window being installed, whereupon the window is hoisted up to and into the window opening by means of a winch mounted to a winch frame positioned inside the building. The risk of the window falling to the ground is considerably reduced or eliminated by the hoist and its associated lifting line, which should remain attached to the lifting harness until the window has been anchored in position. However, the Harrison invention is a complicated apparatus involving numerous components, including moving parts which may wear out. The Harrison apparatus has the further disadvantage of requiring a complicated procedure in operation, both during hoisting and installation of the window, and in dismantling the apparatus after the window has been positioned.
There is therefore a need in the art for a window installation support means which is simple and easy to use, has a minimal number of components, and is simple and economical to manufacture. In particular, there is a need for such a device adapted for use in conventional wood frame building construction wherein the framework for the window openings includes a sill member.